I’ll just say that I have my phone with me practically all the time and WhatsApp work really well for my business’s internal communications (5-man consulting shop). I can ask a question in the middle of a meeting and get potentially four responses in a matter of seconds because everyone gets notified when a new message arrives. I’m not suggesting WhatsApp at all, just suggesting that having notifications of new questions is really useful.
I guess technically you could create one post that is nothing but a hotline and those that want to participate can post to it so they get messages and people needing a quick response should try there first. What’s the lag between posting a message and emails getting sent?